US3673363A

US3673363A - Return mechanism for an automatically returning switch

Info

Publication number: US3673363A
Application number: US42022A
Authority: US
Inventors: Tadahisa Nakamura; Hirozi Fujimoto; Makoto Yamamoto; Yukito Shintomi
Original assignee: Fujisoku Electric Co Ltd
Current assignee: Fujisoku Corp
Priority date: 1969-05-31
Filing date: 1970-06-01
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

Return mechanism for an automatically returning switch comprises a return spring of particular shape and means for mounting this return spring on the switch box. The return spring is made of a spring wire and includes a mounting portion in one plane and an arm, or bridging, portion in another plane, preferably normal thereto, for exerting a spring action on the switch actuator rod. The mounting means for the mounting portion of the spring includes at least one groove in the wall of the switch box which permits one arm portion to move independently of the other arm portion.

Description

United States Patent Nakamura et a1.

[ 1 June 27, 1972 Makoto Yamamoto; Yukito Shintomi, all of Kawasaki, Japan [73] Assignee: Fujisoku Electric Co., Ltd., Kawasaki-shi,

Japan [22] Filed: June 1,1970

[21] Appl.No.: 42,022

[56] References Cited UNITED STATES PATENTS 3,345,488 10/1967 Siegal ..200/153 K 3,333,067 7/1967 Du Rocher et al ..200/6 Primary ExaminerJ. V. Truhe Assistant Examiner-Gale R. Peterson Attorney-Pearson & Pearson [5 7] ABSTRACT Return mechanism for an automatically returning switch comprises a return spring of particular shape and means for mounting this return spring on the switch box. The return spring is made of a spring wire and includes a mounting portion in one plane and an arm, or bridging, portion in another plane, preferably normal thereto, for exerting a spring action on the switch actuator rod. The mounting means for the mounting portion of the spring includes at least one groove in the wall of the switch box which permits one am portion to move independently of the other arm portion.

5 Claims, 9 Drawing Figures PATENTEDJUHZT 1972 3. 673 363 25 E 241 2| Q 23 25 23 J an v 3' 25 22 22 FlG. 5a FlG.5b FlG.5c

INVENTOR T TADAHISA NAKAHURA HIROZI FUIIHO 0 3o 24 24 30 34b MAKOTO YAMANOTO-YUKITO SHINTOIH F l G. 6 BY Ewan-0'" PM ATTORNEY RETURN MECHANISM FOR AN AUTOMATICALLY RETURNING SWITCH BACKGROUND OF THE INVENTION l-leretofore there have been proposed various kinds of return mechanism for an automatically returning switch. Among them, a returning mechanism of lapping plate type and a returning mechanism of coil spring type are the most typical examples, the former including a return plate of an M form mounted on a movable see-saw contact on which a follower slides, and the latter including coil springs arranged at opposite sides of an actuator and utilizing the return force of the coil springs.

The former returning mechanism, however, has drawbacks in that (1) the distance between the topmost points of the M shaped return plate and the ceiling of the switch box cannot be greatly reduced as this would result in deterioration of the electric insulation characteristic of the switch and (2) return plates having different form are required to obtain automatic return action on one ON-position and two opposite ON position of the switch having ON-OFF-ON characteristic.

The latter returning mechanism as mentioned above also has drawbacks in that (1) the distance between the movable see-saw contact and the ceiling of the switch box cannot be greatly reduced due to the vertical arrangement of the switch parts and (2) a greater number of parts are required and production, stocking etc. thereof becomes complex.

Thus, the returning mechanisms according to the prior art were not satisfactory in the sense of reduction in height of the switch, and hence the minituarization thereof.

The principle object of this invention is to provide a returning mechanism for an automatically returning switch having none of the defects of the conventional switch but having more superior technical merits.

SUMMARY OF THE INVENTION The returning mechanism according to this invention is characterized by a returning spring with particular configuration integrally made of a single spring wire, and by fixing means for fixing the returning spring onto a switch box.

The returning mechanism for a switch proposed in this invention comprises at least two terminals projecting from the switch box for connection to outside circuits; a movable seesaw contact in electrical contact with one of said terminals and having a fulcrum on said one terminal and electrically making or breaking contact with the other of said terminals; a rocking actuator rod having means secured at its tip for driving said movable contact; at least one returning spring exerting a return action on said actuator rod; and groove means provided on the switch box for fixing said returning spring thereto, said returning spring consisting of two mounting portions each having a curved portion at its bottom and two bridging portions connecting the upper ends of said mounting portions to each other thereby oppositely spacing said mounting portions, or consisting of a hook portion having a curved portion at its bottom and an arm portion with one end turned approximately at a right angle with respect to the plane containing said hook portion, and said returning spring being made of a single spring wire, and said spring fixing means being a groove provided on the outside surface of the wall of the switch box.

The return spring, which constitutes the main part of the return mechanism of this invention, is made of a single spring wire and is simple in its configuration. This spring is also easy to produce and suitable for mass production. Mounting of the spring on the switch is also simplified by its particular configuration.

It is a more important merit of this invention that the minimum distance between the movable contact and the ceiling of the frame is not at all limited by the switching mechanism. This is because, in assembly, the bridging portions or the arm portion of the return spring of this invention are positioned adjacent to or on the top of the box and the mounting portions or the hook portion of the spring are mounted generally normal thereto in grooves on the side surfaces of the switch box and therefore only the diameter of the spring wire has an efiect on height of the switch. This permits the reduction in height of the switch, and hence in the overall size thereof compared with the switch of prior art.

The above merits result in a decrease of production cost of the switch.

Viewing the return mechanism and in particular the return spring, of this invention from another aspect, it has also advantages in that the life of the spring becomes longer in comparison with the conventional one due to the fact that the tension is exerted all over the spring during operation.

In addition to the above, the applicability of the return spring is greater than that of prior art in consideration of the fact that use of a single return spring provides a switch which automatically returns only in one direction and use of two said return springs provides a switch which automatically returns in two opposite directions.

The invention will be described in greater detail with reference to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of one embodiment of a return spring of the present invention;

FIG. 2 is a perspective view of a switch box for use with the return spring of FIG. 1;

FIG. 3 is a partially sectional plan view of the switch with the return spring of FIG. 1 incorporated and with the top of the frame removed;

FIG. 4 is a partially sectional side view of the switch of FIG.

FIGS. 5a, 5b and 5c are a plan, a front and a perspective view, respectively of another embodiment of a return spring of the present invention;

FIG. 6 is a partially sectional plan view of the switch with the return spring of FIGS. 5a, 5b and 5c incorporated and with the top of the frame removed; and

FIG. 7 is a partially sectional side view of the switch of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The return mechanism according to this invention comprises a return spring with an arm portion on one plane, a mounting portion in another plane and groove means, in said another plane, provided on the switch box for mounting the return spring on the box.

The return spring 1 is made of a single spring wire as shown in FIG. 1, and includes two mounting portions 2, 3 of U shape each having two legs 2a, 2b; 3a, 3b and two

bridging portions

4, 5 each bridging the upper ends of the legs of said two mounting portions 2, 3, said two mounting portions 2 and 3 being oppositely spaced by said bridging

portions

4 and 5. The opposite ends of a single spring wire constituting the return spring 1 form a closed loop and meet each other at the central lower point of the mounting portion 3 as clearly shown in FIG. 1. The

bridging portions

4 and 5 extend in parallel to each other and in spaced relationship so as to receive an actuator rod 12 (FIG. 4) therebetween.

The switch box 6 on which the return spring 1 is mounted and which constitutes a part of the return mechanism of this invention is shown in FIG. 2. This box 6 has two U shaped

grooves

9, 10 on opposite side walls 7, 8 for receiving

legs

20, 2b and 3a, 3b of the mounting portions 2 and 3 of the spring 1. The U shaped groove is of fixed width at its two legs and becomes narrower toward the central lowest point.

In assembly, the return spring 1 is positioned astride of the box 6 from above, and the

legs

2a, 2b and 3a, 3b of the mounting portions 2 and 3 are set into the

grooves

9 and 10, respectively, thereby retaining the spring 1 rockingly. When mounted, the mounting portion is sustained at its central lowest point by the inside wall 10a of the groove and therefore a gap is provided between the

bridging portions

4, 5 and top surface of the box 6 as seen from FIG. 4. The actuator rod 12 with a driving means 13 fixed at its tip for actuating the movable see-saw contact 11 is put between the

bridging portions

4 and 5 of the spring I. This rod 12 with a sleeve (not shown) put thereon .is secured to the top plate of the frame 14 rockingly. The

frame plates

14a, 14b extending downward at opposite sides of the box 6 cover the

legs

20, 2b and 3a, 3b of the spring I from outside of the box 6. The sleeve, driving means and movable see-saw contact may be of any structure and thus no detailed explanation thereof is made in the specification.

The operation of the switch with the above mentioned arrangement will be described below:

In FIGS. 3 and 4, the actuator rod 12 is in its center position and thus the circuits connected to the

outside terminals

15, 16 and 17 are in off condition.

In this condition, when the actuator rod 12 is moved in the direction A by a force applied thereto, the rod 12 pushes the bridging portion 5 of the return spring 1 leftward and takes the position as represented by a dotted line in FIG. 4. This results in that the movable see-saw contact 11 is tilted by the driving means 13 to lower the left end thereof to its lowest position and to close the circuit connected to the terminals and 16., In this operation, the leg 3a of the mounting portion 3 of the spring 1 opens outwardly relative to the central lowest point 30. The actuator rod 12 continues to retain this condition so long as such a force is applied. As shown, the

legs

2b and 3b do not flex in the direction A and remain seated against the walls of the islands of their

respective grooves

9 and 10. Thus the force exerted on the actuator rod 12 comes from deflection of the left half of the spring, substantially independent of any force coming from the right half thereof, the right half remaining anchored in its half of the grooves. The force necessary to drive the actuator rod 12 is therefore minimized and operation is by a relatively light touch. When the force exerted on the rod 12 is removed, the rod 12 is caused to return to its center position by the spring restitution force stored in the bridging portion 5 and the circuits connected to the terminals I5 and I6 are opened.

Similarly, when the actuator rod 12 is moved in the direction B by a force applied thereto, the bridging portion 4 is moved rightward and the circuit as connected to the terminals I6 and 17 is closed. With this force removed, the circuit is opened.

Explanation will be made on another embodiment of the return spring according to this invention with reference to FIGS. 5a, 5b and 5c.

This return spring 21 is also made of a single spring wire, and includes a hook portion 22 and an arm portion 24, the latter being bent approximately at a right angle at the end 23 of the straight portion of said hook portion with respect to a plane containing said hook portion, and extending a desired distance from the plane.

In assembly, the return spring 1 is so mounted on the box 26 that the hook portion 22 of the spring 21 is set into a groove 29 provided on a side wall 27 of the box 26, and that the free end 25 of the hook portion 22 abuts on the inside wall of the groove 29 and that the bent portion 23 is positioned on the top edge of the box 26 and that the arm portion 24 is positioned in contact with the actuator rod 32. Another return spring is also mounted on the opposite side wall 28 of the box 26 similarly. The shape of the grooves 29, 30 on the side walls 27, 28 of the box 26 need not necessarily be similar to that shown in FIG. 2.

When two return springs 21 are mounted on the same box 26, the

arm portions

24, 24 are juxtaposed and hold therebetween an actuator rod 32 with a sleeve (not shown) thereon. This rod 32 is also secured to the top plate of the frame 34 rockingly. The rod 32 has a driving means 33 fixed at its tip for tilting the movable see-saw contact 31. The frame plates 34a and 34b of the frame 34 cover each hook portions 22 from the outside thereof.

The operation of the switch with the return spring as mentioned above will be described in connection with FIGS. 6 and 7 In these drawings, the actuator rod 32 is in its center position and the circuits connected to the

outside terminals

35, 36 and 37 are in off condition.

In this condition, when the actuator rod 32 is moved in the direction A" against the arm portion 24 of the spring 21 by a force applied thereto, the rod 32 presses the arm portion 24 leftward, and thus the hook portion 22 expands with respect to the free end 25 thereof abutting on the inner wall of the groove.

The rod 12 and the spring I take the position as shown in FIG. 7 by a dotted line. The driving means 33 secured at the tip of the rod 32 tilts the movable see-saw contact 31 to its lowest position to close the outside circuits connected to the

terminals

35 and 36. When the force applied to the rod 32 is removed, the rod 32 returns to its center position by the restitution force stored in the arm portion 24 of the spring 1, and the circuit opens.

Similarly, when the actuator rod 32 is moved in the direction B by an applied force, the driving means 33 tilts the movable contact 31 to its opposite lowest position to close the outside circuits connected to the

terminals

36 and 37. When the applied force is removed, the rod 32 returns to its center position by the spring restitution force of the spring.

In the second embodiment as above mentioned, two similar return springs are used for the actuator rod to automatically return to its center position in two opposite directions. Ifa one way return is desired, however, a single return spring may be used. This is effective in increasing the usages of the switch.

It is a matter of course that the return mechanism according to this invention is well applicable not only to a toggle switch but also to any switch.

It is to be understood that the embodiments described herein are illustrative only and are not intended as limiting the invention to the construction and arrangement of parts described.

We claim I. Automatically returning switch comprising:

at least two terminals projecting from a switch box for connection to an outside circuit or circuits,

a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box so as to make or break electrical contact with the other terminal or terminals,

a rocking actuator with driving means secured at the tip thereof for driving said see-saw contact,

two return springs exerting a spring action on said actuator,

and

means provided on said switch box for fixing said return springs thereto,

said returning springs each consisting of a hook portion having a curved portion at its bottom and an arm portion with one end turned approximately at a right angle with respect to the plane containing said hook portion,

said spring fixing means being a groove provided on the outside surface of the opposite walls of the switch box and having an island within said groove, and said island having a curvature at its lower part conforming to said curved portion of said hook portion of the spring said two return springs being mounted within each of said grooves on said switch box so that the arm portions of said springs can receive said actuator therebetween.

2. An automatically returning switch comprising:

at least two terminals projecting from a switch box for connection to an outside circuit, or circuits;

a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box so as to make or break electrical contact with the other terminal or terminals;

a rocking actuator with driving means secured at the top thereof for driving said see-saw contact;

return spring means exerting a return action on said actuator, said means including two arm portions, each on an opposite side of said actuator, and each having a mounting portion extending substantially normal thereto; and

spring receiving means on said switch box for receiving said mounting portions, each said spring receiving means including a groove in the outside surface of one of the walls of said switch box and an island within said groove;

whereby said mounting portions have predetermined deflection movement in said grooves.

3. An automatically returning switch comprising:

return spring means exerting a return action on said actuator, said means including two arm portions, each on an opposite side of said actuator, and each having a mounting portion extending substantially normal thereto;

spring receiving means on said switch box for receiving said mounting portions, each said spring receiving means including a groove in the outside surface of one of the walls of said switch box and an island within said groove; and

said return spring means comprising a spring wire with the said mounting portions thereof generally of U-shape and each said groove being of U-shape with legs of predetermined width and a central, curved, lower portion of reduced width;

whereby said mounting portions have predetermined deflection movement in the legs of said grooves.

4. An automatically returning switch comprising:

a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box to make or break electrical contact with the other terminal or terminals;

said return spring means comprising a single spring wire forming a symmetrical closed loop;

5. An automatically returning switch comprising:

spring receiving means on said switch box for receiving said mounting portions, each said spring receiving means including a groove in the outside surface of one of the walls of said switch box and an island within saidgroove; and said return spring means comprises a pair of Identical springs each having a hook portion with a curve at its bottom forming said mounting portion and each having said am portion at its top with one end turned approximately at a right angle with respect to the plane containing said hook portion, each said arm portion being positioned in contact with an opposite side of said actuator of the switch, the said hook portion having a free end in engagement with the island of the groove in which it is received;

Claims

1. Automatically returning switch comprising: at least two terminals projecting from a switch box for connection to an outside circuit or circuits, a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box so as to make or break electrical contact with the other terminal or terminals, a rocking actuator with driving means secured at the tip thereof for driving said see-saw contact, two return springs exerting a spring action on said actuator, and means provided on said switch box for fixing said return springs theretO, said returning springs each consisting of a hook portion having a curved portion at its bottom and an arm portion with one end turned approximately at a right angle with respect to the plane containing said hook portion, said spring fixing means being a groove provided on the outside surface of the opposite walls of the switch box and having an island within said groove, and said island having a curvature at its lower part conforming to said curved portion of said hook portion of the spring said two return springs being mounted within each of said grooves on said switch box so that the arm portions of said springs can receive said actuator therebetween.

2. An automatically returning switch comprising: at least two terminals projecting from a switch box for connection to an outside circuit, or circuits; a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box so as to make or break electrical contact with the other terminal or terminals; a rocking actuator with driving means secured at the top thereof for driving said see-saw contact; return spring means exerting a return action on said actuator, said means including two arm portions, each on an opposite side of said actuator, and each having a mounting portion extending substantially normal thereto; and spring receiving means on said switch box for receiving said mounting portions, each said spring receiving means including a groove in the outside surface of one of the walls of said switch box and an island within said groove; whereby said mounting portions have predetermined deflection movement in said grooves.

3. An automatically returning switch comprising: at least two terminals projecting from a switch box for connection to an outside circuit, or circuits; a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box so as to make or break electrical contact with the other terminal or terminals; a rocking actuator with driving means secured at the top thereof for driving said see-saw contact; return spring means exerting a return action on said actuator, said means including two arm portions, each on an opposite side of said actuator, and each having a mounting portion extending substantially normal thereto; spring receiving means on said switch box for receiving said mounting portions, each said spring receiving means including a groove in the outside surface of one of the walls of said switch box and an island within said groove; and said return spring means comprising a spring wire with the said mounting portions thereof generally of U-shape and each said groove being of U-shape with legs of predetermined width and a central, curved, lower portion of reduced width; whereby said mounting portions have predetermined deflection movement in the legs of said grooves.

4. An automatically returning switch comprising: at least two terminals projecting from a switch box for connection to an outside circuit, or circuits; a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box to make or break electrical contact with the other terminal or terminals; a rocking actuator with driving means secured at the top thereof for driving said see-saw contact; return spring means exerting a return action on said actuator, said means including two arm portions, each on an opposite side of said actuator, and each having a mounting portion extending substantially normal thereto; spring receiving means on said switch box for receiving said mounting portions, each said spring receiving means including a groove in the outside surface of one of the walls of said switch box and an island within said groove; and said return spring means comprising a single spring wire forming a symmetrical closed loop; whereby said mounting portions have predetermined deflection movement in said grooVes.

5. An automatically returning switch comprising: at least two terminals projecting from a switch box for connection to an outside circuit, or circuits; a see-saw contact in electrical contact with one of said terminals and adapted to rock within said box to make or break electrical contact with the other terminal or terminals; a rocking actuator with driving means secured at the top thereof for driving said see-saw contact; return spring means exerting a return action on said actuator, said means including two arm portions, each on an opposite side of said actuator, and each having a mounting portion extending substantially normal thereto; spring receiving means on said switch box for receiving said mounting portions, each said spring receiving means including a groove in the outside surface of one of the walls of said switch box and an island within said groove; and said return spring means comprises a pair of identical springs each having a hook portion with a curve at its bottom forming said mounting portion and each having said arm portion at its top with one end turned approximately at a right angle with respect to the plane containing said hook portion, each said arm portion being positioned in contact with an opposite side of said actuator of the switch, the said hook portion having a free end in engagement with the island of the groove in which it is received; whereby said mounting portions have predetermined deflection movement in said grooves.